Nowadays, portable media players such as portable CD players, MP3 players and the like become popular in modern societies due to some advantages such as small size, light weightiness and easy portability. On account of their portability, the users can use such portable media players everywhere they are. In order to hear songs from the portable media player, some accessories such as earphones are indispensable. Since the structure of the earphones may influence the tone quality and the portability of the portable media player, it is important to select suitable earphones matching the portable media player.
Generally, the earphone devices offered by the manufacturers of the portable CD players or the MP3 players are plain earplug types, which have plain sound isolation and plain tone quality. When this earplug type earphone device is used, the volume of the portable CD player or the MP3 player is unconsciously turned up to a high level because the noisy sounds in the surroundings are not effectively isolated. After exposure to such a noisy environment for a long term, the user is readily suffered from hearing loss. For a purpose of protecting from hearing loss, a headphone device having ear muffs is additionally purchased. The headphone device is usually divided into two categories: a vertical headphone device that arches over the head and a horizontal headphone device that rests on the ears. The vertical headphone device that arches over the head is both bulky and cumbersome for the portable use in the portable CD player or the MP3 player. Whereas, the horizontal headphone device that rests on the ears includes a pair of supporting members for supporting the speaker units. According the user's demand, the horizontal headphone device is attached to the rear head of a user as the supporting members rest on the ears. Typically, the vertical headphone device that arches over the head has a rigid hoop structure, and is therefore not feasible for portability or storage. Whereas, the horizontal headphone device that rests on the ears is advantageous for portability or storage because no rigid hoop structure is used. In comparison with the earplug type earphone device, however, the horizontal headphone device is unsatisfactory in portability or storage because the overall volume of the horizontal headphone device is increased and the two speaker units are distant from each other.
For a purpose of solving the drawbacks described above, as shown in FIG. 1(a), an improved headphone device is disclosed in U.S. Pat. No. 6,385,325 B1, which is hereby fully incorporated by reference. Referring to FIG. 1(a), the headphone device 1 comprises a rigid hoop structure 11, a first supporting member 12, a second supporting member 13, a first speaker unit 14 and a second speaker unit 15. The hoop structure 11 is rotatable about a first fulcrum portion 111 in the direction indicated by the arrow A. The first supporting member 12 and the second supporting member 13 are coupled with the hoop structure 11. When the headphone device 1 is attached to the rear head of a user, the first supporting member 12 and the second supporting member 13 rest on the user's ears. The first speaker unit 14 and the second speaker unit 15 are supported by the first supporting member 12 and the second supporting member 13, respectively. The first supporting member 12 and the second supporting member 13 are rotatable about a second fulcrum portion 121 and a third fulcrum portion 131, respectively, in the direction indicated by the arrow B. For collapsing the headphone device 1, the first fulcrum portion 111 of the hoop structure 11, the second fulcrum portion 121 of the first supporting member 12 and the third fulcrum portion 131 of the second supporting member 13 are cooperatively operated. First of all, as shown in FIG. 1(b), the first supporting member 12 and the second supporting member 13 are rotated in the direction indicated by the arrow B about the second fulcrum portion 121 and the third fulcrum portion 131, respectively, so that the first speaker unit 14 and the second speaker unit 15 along with the supporting member 12 and the second supporting member 13 approach toward the hoop structure 11. Then, the hoop structure 11 is rotated in the direction indicated by the arrow A, so that the first speaker unit 14 and the second speaker unit 15 approach each other. Afterwards, the first speaker unit 14 and the second speaker unit 15 are housed in a region surrounded by the first supporting member 12, the second supporting member 13 and the hoop structure 11, as can be seen in FIG. 1(c).
Although the headphone device of FIG. 1 is storable when collapsed to a compact size, this headphone device still has some drawbacks. For example, since the hoop structure 11 is made of rigid material, the compact size is not satisfied. As shown in FIG. 1(c), due to the rigid hoop structure 11, there is still large space between the first speaker unit 14 and the second speaker unit 15. Therefore, there is a need to collapse the headphone device to a reduced size. In addition, the first fulcrum portion 111, the second fulcrum portion 121 and the third fulcrum portion 131 are readily loosened after many rotating and collapsing cycles. Under this circumstance, the headphone device fails to be well collapsed.
In views of the above-described disadvantages resulted from the prior art, the applicant keeps on carving unflaggingly to develop a headphone device according to the present invention through wholehearted experience and research.